Known catalysts and methods exist to convert synthesis gas (syngas) to fuels and chemicals. One exemplary method includes Fischer-Tropsch synthesis (FTS), but because FTS products are controlled by Anderson-Schulz-Flory (ASF) polymerization kinetics, FTS does not provide for selective formation of hydrocarbons. Also, since the hydrocarbon products contain only carbon (C) and hydrogen (H), oxygen (O) will be released as the byproducts of CO2 and H2O in the FTS process, thereby decreasing the overall efficiency of the process. To improve the overall efficiency, C, H, and O can be kept in the final products, thereby increasing the utilization of syngas. Another approach is to first convert syngas to methanol over a methanol synthesis catalyst, and subsequently polymerize methanol to hydrocarbons. These known methods generally utilize nitrogen-free syngas or low-level nitrogen syngas derived from natural gas or coal, pure syngas, or other low nitrogen syngas.
In this regard, some have attempted to utilize biomass to produce energy-related products such as electricity, fuels, heat, chemicals, and other materials. Biomass can be desirable because it can be renewable. However, because the syngas from biomass gasification can contain about 50 vol % to about 60 vol % N2, the nitrogen content in biomass syngas is generally too high for hydrocarbon synthesis using existing technologies. For example, catalysts designed for the syngas-to-gasoline processes have low performance with such high nitrogen content, and the operation costs of syngas compression is a significant investment.
Additionally, while the syngas from biomass and other sources is fairly clean, some impurities, such as H2S, NH3, and O2, do exist. Such impurities in the syngas can “poison” the catalyst and thus reduce conversion efficiency. Generally, a qualified clean syngas should have minimal amounts of sulfurs, such as H2S, COS, NH3, and oxygen.
Accordingly, there remains a need for a high activity and high stability catalyst useful for converting syngas, including nitrogen-rich and/or biomass derived syngas (bio-syngas), into hydrocarbons. There also remains a need for multi-functional catalysts for a single-stage syngas-to-hydrocarbon process that can be utilized with nitrogen-rich bio-syngas.